After this, the graphical interface didn’t work (a bad fglrx: No matching Device section for instance (BusID PCI:0@0:1:1) at boot-up)… This is because there is one more step to do (which is not present in the aforementioned guide):in the BIOS, the option Switchable graphic needs to be set to Discrete

This is a solution to SD mounting problems of a Realtek RTS5209 card read.
This affects my new Sony Vaio (SVE151G) with Linux Mint 15 but the solution can be extended to other operating systems/PCs (Ubuntu for example, and some HP notebooks).

Basically, when a SD card is inserted nothing happens… The device is not mounted and DMESG command says something like:

A friend of mine bought this vintage keyboard: a Farfisa Matador (Mod. 611-E) coming directly from the ’70s. By the way the seller forgot to mention that, despite being very well conserved on the outside, it produced a strong and unpleasant hiss that made it almost unusable; it sounded like a out-of-tune chord, so the guy said it was just some dirt under the keys. False…

So I had the honour to put my hands inside this beautiful keyboard. I want to share this experience with you posting some photos I made during the troubleshoot process (se serve una traduzione in italiano chiedete nei commenti).

In the past I already tested a nice boost circuit that allows us to power a 3 V LED with a discharged battery (around 1 V or less). This circuit uses just one transistor, one resistor and a small transformer (1:1 ratio) and it is better known, at least on the internet, under the name of “Joule Thief”.

The theory behind this circuit seems to be obscure as we can find lot of comments and questions like: “can I add turns ?”, “can I increase the resistor ?”, “will it work with two batteries ?” and so on…

I decided to figure out the working mechanism of this smart circuit in order to understand the rules behind it and try to improve the efficiency. I’ll carry out a theoretical analysis, supported by some scope screen-shots.

I wanted to create a 9600 asynchronous serial connection with my TI LaunchPad.
I started my development from the source code of the example program that I found in it (temp. sensor with serial connection and leds modulation) but I wanted three more things: a faster link (9600 which is four times greater), a mspgcc4 compatibility (the free-software compiler that I’m using) and a CPU working at 16 MHz (instead of 1 MHz of the example).

The task is not very difficult and I carried it in a completely free environment (Ubuntu + MSPGCC + mspDebug).Continue reading →